org.apache.commons.logging

Interface Log

Known Implementing Classes:
AvalonLogger, Jdk13LumberjackLogger, Jdk14Logger, Log4JCategoryLog, Log4JLogger, LogKitLogger, NoOpLog, SimpleLog

public interface Log

A simple logging interface abstracting logging APIs. In order to be instantiated successfully by LogFactory, classes that implement this interface must have a constructor that takes a single String parameter representing the "name" of this Log.

The six logging levels used by Log are (in order):

  1. trace (the least serious)
  2. debug
  3. info
  4. warn
  5. error
  6. fatal (the most serious)
The mapping of these log levels to the concepts used by the underlying logging system is implementation dependent. The implemention should ensure, though, that this ordering behaves as expected.

Performance is often a logging concern. By examining the appropriate property, a component can avoid expensive operations (producing information to be logged).

For example,

    if (log.isDebugEnabled()) {
        ... do something expensive ...
        log.debug(theResult);
    }
 

Configuration of the underlying logging system will generally be done external to the Logging APIs, through whatever mechanism is supported by that system.

Version:
$Id: Log.java,v 1.19 2004/06/06 21:16:04 rdonkin Exp $
Authors:
Scott Sanders
Rod Waldhoff

Method Summary

void
debug(Object message)
Log a message with debug log level.
void
debug(Object message, Throwable t)
Log an error with debug log level.
void
error(Object message)
Log a message with error log level.
void
error(Object message, Throwable t)
Log an error with error log level.
void
fatal(Object message)
Log a message with fatal log level.
void
fatal(Object message, Throwable t)
Log an error with fatal log level.
void
info(Object message)
Log a message with info log level.
void
info(Object message, Throwable t)
Log an error with info log level.
boolean
isDebugEnabled()
Is debug logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than debug.

boolean
isErrorEnabled()
Is error logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than error.

boolean
isFatalEnabled()
Is fatal logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than fatal.

boolean
isInfoEnabled()
Is info logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than info.

boolean
isTraceEnabled()
Is trace logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than trace.

boolean
isWarnEnabled()
Is warn logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than warn.

void
trace(Object message)
Log a message with trace log level.
void
trace(Object message, Throwable t)
Log an error with trace log level.
void
warn(Object message)
Log a message with warn log level.
void
warn(Object message, Throwable t)
Log an error with warn log level.

Method Details

debug

public void debug(Object message)
Log a message with debug log level.
Parameters:
message - log this message

debug

public void debug(Object message,
                  Throwable t)
Log an error with debug log level.
Parameters:
message - log this message
t - log this cause

error

public void error(Object message)
Log a message with error log level.
Parameters:
message - log this message

error

public void error(Object message,
                  Throwable t)
Log an error with error log level.
Parameters:
message - log this message
t - log this cause

fatal

public void fatal(Object message)
Log a message with fatal log level.
Parameters:
message - log this message

fatal

public void fatal(Object message,
                  Throwable t)
Log an error with fatal log level.
Parameters:
message - log this message
t - log this cause

info

public void info(Object message)
Log a message with info log level.
Parameters:
message - log this message

info

public void info(Object message,
                 Throwable t)
Log an error with info log level.
Parameters:
message - log this message
t - log this cause

isDebugEnabled

public boolean isDebugEnabled()
Is debug logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than debug.


isErrorEnabled

public boolean isErrorEnabled()
Is error logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than error.


isFatalEnabled

public boolean isFatalEnabled()
Is fatal logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than fatal.


isInfoEnabled

public boolean isInfoEnabled()
Is info logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than info.


isTraceEnabled

public boolean isTraceEnabled()
Is trace logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than trace.


isWarnEnabled

public boolean isWarnEnabled()
Is warn logging currently enabled?

Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than warn.


trace

public void trace(Object message)
Log a message with trace log level.
Parameters:
message - log this message

trace

public void trace(Object message,
                  Throwable t)
Log an error with trace log level.
Parameters:
message - log this message
t - log this cause

warn

public void warn(Object message)
Log a message with warn log level.
Parameters:
message - log this message

warn

public void warn(Object message,
                 Throwable t)
Log an error with warn log level.
Parameters:
message - log this message
t - log this cause

Copyright 2002-2004 The Apache Software Foundation.